1. Field of the Invention
The present invention relates to a photoelectric conversion devices.
2. Description of the Related Art
Recently, a photoelectric conversion device that generates power without carbon dioxide emissions has attracted attention as a countermeasure against global warming. As a typical example thereof, a solar cell has been known which uses a crystalline silicon substrate such as a single crystalline substrate or a polycrystalline silicon substrate.
In solar cells using a crystalline silicon substrate, a structure having a so-called homo junction is widely used. In such a structure, a layer having the conductivity type opposite to that of the crystalline silicon substrate is formed on one surface side of the crystalline silicon substrate by diffusion of impurities.
Further, solar cells are disclosed in Patent Documents 1 and 2 in each of which a heterojunction is formed by formation of an amorphous silicon layer having an optical bandgap and a conductivity type which are different from those of a crystalline silicon substrate on one surface or both surfaces of the crystalline silicon substrate so that interface properties are improved.